Method and apparatus for forming three-dimensional image

ABSTRACT

There are provided a method and apparatus for forming a three-dimensional image. The method and apparatus form an arbitrary colored image on the surface of a thermally expandable sheet by using surface image data. The method and apparatus form a mirror image, of which the density of a black component is adjusted in consideration of the influence of the density of the colored image on a bulge height of a thermally expandable layer so that an originally scheduled bulge height can be achieved, on the back of the thermally expandable sheet. The method and apparatus can achieve an intended bulge height by expanding the thermally expandable layer with thermal energy that is generated in the mirror image and the colored image when the thermally expandable sheet is irradiated with light including infrared wavelengths from the back of the thermally expandable sheet.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority based on Japanese Patent ApplicationNo. 2011-282836, filed on Dec. 26, 2011, the entire contents of whichare incorporated by reference herein.

BACKGROUND OF THE INVENTION

Field

The present invention relates to a method and apparatus for forming athree-dimensional image, and more particularly, to a method andapparatus for forming a three-dimensional image by selectively expandinga thermally expandable sheet.

Background

A thermally expandable sheet (or a thermally foamable sheet) where athermally expandable layer (or a foamable layer) containing foamablemicrocapsules expanding due to heating is formed on one surface of abase sheet has been known in the past. When the thermally expandablesheet is irradiated with light including infrared light after an imagepattern having a high light absorption property is printed on thisthermally expandable sheet, the region of the thermally expandable layercorresponding to the image pattern is selectively heated and expanded.Accordingly, it is possible to form a three-dimensional image, whichcorresponds to the image pattern, on one surface of the base sheet.

As the technique for forming a three-dimensional image, for example,JP-A-64-28660 discloses a method including forming a print image usingblack toner or ink having a high light absorption property on thesurface of a thermally expandable sheet that corresponds to a thermallyexpandable layer, or on the back of the thermally expandable sheet thatcorresponds to a base sheet; and forming a three-dimensional image byheating and expanding (foaming) the microcapsules of the region of thethermally expandable layer corresponding to the print image byirradiating the thermally expandable sheet with light from a halogenlamp or the like so that light is absorbed in the print image and heatis generated.

Further, for example, JP-A-2001-150812 discloses a method includingforming a color image or the like on the surface of the thermallyexpandable sheet that corresponds to a thermally expandable layer;forming a light absorption pattern, which is formed of a grayscale imageso as to correspond to the pattern of the color image formed on thesurface, on the back of the thermally expandable sheet that correspondsto a base sheet; generating heat corresponding to the grayscale of thelight absorption pattern by irradiating the thermally expandable sheetwith light from the back of the thermally expandable sheet; andcontrolling the degree of the expansion of the thermally expandablelayer to adjust the bulge height of a three-dimensional image.

According to the method disclosed in JP-A-2001-150812, it is possible toform a three-dimensional image of which an arbitrary portion iscontrolled to have an arbitrary bulge height (foam height) according tothe pattern of the color image or the like that is formed on the surfaceof the thermally expandable sheet corresponding to the thermallyexpandable layer.

However, according to the result of the inventor's verification of thesemethods of forming a three-dimensional image, it is found that the bulgeheight of the three-dimensional image is affected by the grayscale ofthe color image or the like formed on the surface of the thermallyexpandable sheet corresponding to the thermally expandable layer inaddition to the grayscale of the light absorption pattern formed on theback of the thermally expandable sheet corresponding to the base sheet.For this reason, when the density of the light absorption pattern formedon the back is set so as to correspond to the pattern or the like of thecolor image formed on the surface of the thermally expandable sheet andthe irradiation of light is performed, the three-dimensional imageexceeds an intended bulge height in some grayscales of the color imageor the like. Accordingly, there is a problem in that a goodthree-dimensional image may not be formed. Meanwhile, the problem in therelated art will also be described in detail in the detailed descriptionto be described below.

SUMMARY

The invention has been made in consideration of the above-mentionedcircumstances, and an object of the invention is to provide a method andapparatus for forming a three-dimensional image that can achieve anintended bulge height in consideration of the influence of the grayscaleof a print image formed on the surface of a thermally expandable sheetwhen the thermally expandable sheet is irradiated with light to form athree-dimensional image.

In order to achieve the above-mentioned object of the invention,according to an aspect of the invention, there is provided a method offorming a three-dimensional image including: forming a first print imageon one surface of a thermally expandable sheet where a thermallyexpandable layer is formed on the one surface of a base sheet; forming asecond print image on a region of the other surface of the thermallyexpandable sheet, the second print image being to be a mirror image ofthe first print image, the region of the other surface corresponding tothe first print image of the one surface, and a density of aphotothermal conversion material contained in the second print imagebeing set based on a density of a photothermal conversion materialcontained in the first print image; and forming a three-dimensionalimage of the first print image by selectively expanding the thermallyexpandable layer with thermal energy that is generated in the secondprint image when irradiating the thermally expandable sheet with lightfrom the other surface of the thermally expandable sheet.

Further, in order to achieve the above-mentioned object of theinvention, according to another aspect of the invention, there isprovided an apparatus for forming a three-dimensional image including: aprint function unit and an image processing unit. The print functionunit forms a first print image on one surface of a thermally expandablesheet where a thermally expandable layer is formed on the one surface ofa base sheet and forms a second print image on a region of the othersurface of the thermally expandable sheet with a photothermal conversionmaterial. The second print image is to be a mirror image of the firstprint image. The region of the other surface corresponds to the firstprint image of the one surface. The image processing unit sets a densityof the photothermal conversion material contained in the second printimage based on a density of a photothermal conversion material containedin the first print image. A three-dimensional image of the first printimage is formed by selectively expanding the thermally expandable layerwith thermal energy that is generated according to at least the densityof the photothermal conversion material contained in the second printimage when the thermally expandable sheet is irradiated with light fromthe other surface of the thermally expandable sheet.

According to the method and apparatus for forming a three-dimensionalimage of the aspect of the invention, it is possible to achieve anintended bulge height in consideration of the influence of the grayscaleof a print image formed on the surface of a thermally expandable sheetwhen the thermally expandable sheet is irradiated with light to form athree-dimensional image.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of this application can be obtained whenthe following detailed description is considered in conjunction with thefollowing drawings, in which:

FIG. 1 is a flow chart illustrating an example of a method of forming athree-dimensional image according to the invention;

FIGS. 2A, 2B, and 2C are schematic plan views illustrating a method offorming a three-dimensional image according to a comparative example;

FIGS. 3A, 3B, 3C, and 3D are schematic cross-sectional viewsillustrating the method of forming a three-dimensional image accordingto the comparative example;

FIGS. 4A and 4B are views illustrating an analytical method of themethod of forming a three-dimensional image according to the comparativeexample;

FIG. 5 is a view illustrating, the concept of a data processing methodof a method of forming a three-dimensional image according to anembodiment of the invention (the results of the analysis of thecomparative example);

FIGS. 6A, 6B, and 6C are schematic plan views showing a specific exampleof the method of forming a three-dimensional image according to theembodiment of the invention;

FIGS. 7A, 7B, 7C, and 7D are schematic cross-sectional views showing aspecific example of the method of forming a three-dimensional imageaccording to the embodiment of the invention;

FIGS. 8A and 8B are schematic views showing an example of a printer thatis applied to an apparatus for forming a three-dimensional imageaccording to the invention;

FIG. 9 is a schematic view showing an example of a printing mechanism ofthe printer applied to an embodiment of the invention; and

FIG. 10 is a functional block diagram of an example of the printerapplied to the embodiment of the invention.

DETAILED DESCRIPTION

A method and apparatus for forming a three-dimensional image accordingto the invention will be described in detail below with reference toembodiments.

<Method of Forming Three-Dimensional Image>

First, a method of forming a three-dimensional image according to theinvention will be described.

FIG. 1 is a flow chart illustrating an example of a method of forming athree-dimensional image according to the invention.

As shown in FIG. 1, the method of forming a three-dimensional imageaccording to an embodiment substantially includes image data generationprocessing (S101), surface image formation processing (S102), back imageformation processing (S103), and light irradiation/heating processing(S104).

In the image data generation processing (S101), the image data of anarbitrary colored image that is to be a target of a three-dimensionalimage (hereinafter, referred to as “surface image data”) and a thermallyexpandable sheet on which a three-dimensional image of the colored imageto be formed are prepared first. Here, the thermally expandable sheet isa sheet where a thermally expandable layer (foamable layer) containingfoamable microcapsules is formed on one surface of a base sheet asdescribed above. Further, the colored image may be a color image and maybe a monochrome image or a monotone image.

After that, the density data of a black component, which is set in aspecific region or pixels such as a pattern of the colored image, isextracted on the basis of the surface image data. Further, the bulgeheight (foam height) data of the thermally expandable layer, which arescheduled in the specific region or the like when the thermallyexpandable sheet is heated to form a three-dimensional image, areextracted. Furthermore, image data where the density of a blackcomponent of a specific portion, which corresponds to the specificregion or the like, of a mirror image, which is an inverted image of thecolored image, are set (hereinafter, referred to as “back image data”)are generated on the basis of the density data and the bulge height databy a data processing method to be described below. Meanwhile, in thisspecification, a black component is not limited to black as a color andmeans a photothermal conversion material that generates thermal energyby absorbing light including infrared wavelengths. For example, carbonblack is applied as such a photothermal conversion material.

In the image data generation processing (S101), a data processing methodof setting the density of a black component of the specific portion ofthe mirror image is performed conceptually as follows. That is, whenlight irradiation/heating processing to be described below is performed,the bulge height of the thermally expandable layer of the thermallyexpandable sheet depends on the density of a black component of a mirrorimage that is formed on the back of the base sheet of the thermallyexpandable sheet. In addition to this, the bulge height of the thermallyexpandable layer is also affected by the density of a black componentthat is included in a colored image formed on the surface of thethermally expandable sheet corresponding to the thermally expandablelayer. Accordingly, in this embodiment, the density of a black componentof the mirror image formed on the back (the surface corresponding to thebase sheet) of the thermally expandable sheet is adjusted inanticipation of (in consideration of) the influence of a blackcomponent, which is included in the colored image formed on the surface(the surface corresponding to the thermally expandable layer) of thethermally expandable sheet, on the bulge height of the thermallyexpandable layer so that the originally scheduled bulge height can beachieved. Meanwhile, this data processing method will be described indetail in the verification of an effect to be described below.

Then, in the surface image formation processing (S102), an arbitrarycolored image is formed (printed) using the prepared surface image dataon the surface of the thermally expandable sheet. Here, variousprinters, such as an inkjet printer, a laser printer, and a thermaltransfer printer, mentioned in an apparatus for forming athree-dimensional image to be described below can be applied to form thecolored image on the surface of the thermally expandable sheet.

After that, in the back image formation processing (S103), a blackmirror image, which is set to a predetermined density, is formed(printed) using the back image data, which are generated by the dataprocessing method, on the back of the thermally expandable sheet so asto correspond to the position of the colored image formed on the surfaceof the thermally expandable sheet. Here, various printers, such as aninkjet printer, a laser printer, and a thermal transfer printer,mentioned in an apparatus for forming a three-dimensional image to bedescribed below can also be applied to form the mirror image on the backof the thermally expandable sheet.

Then, in the light irradiation/heating processing (S104), the thermallyexpandable sheet where the colored image is formed on the surface andthe mirror image is formed on the back as described above is uniformlyirradiated with light, which includes infrared wavelengths, from theback of the thermally expandable sheet by a light source, such as ahalogen lamp or an infrared lamp. Accordingly, the density of a blackcomponent is adjusted on the basis of the density of a black componentcontained in the colored image formed on the surface of the thermallyexpandable sheet, so that thermal energy is generated in the mirrorimage formed on the back of the thermally expandable sheet through theabsorption of the irradiation light. As a result, the region of thethermally expandable layer corresponding to the mirror image is heated.Further, at this time, thermal energy is also generated in the region ofthe colored image, which corresponds to the mirror image, according tothe density of a contained black component. As a result, the region ofthe thermally expandable layer corresponding to the colored image isfurther heated.

The microcapsules of the corresponding region of the thermallyexpandable layer expand (foam) due to the thermal energy that isgenerated in the mirror image formed on the back of the thermallyexpandable sheet and the colored image formed on the surface of thethermally expandable sheet as described above. Accordingly, thethermally expandable layer bulges to a scheduled (that is, a presetpredetermined) height, so that an intended three-dimensional image isformed.

Next, the data processing method of the above-mentioned method offorming a three-dimensional image and the effect thereof will bespecifically verified with reference to a comparative example. Here, acase where a three-dimensional image is formed by expanding a thermallyexpandable layer, which is formed on the surface of a thermallyexpandable sheet where an intended colored image is formed on thesurface, to a uniform and intended bulge height will be described tomake the gist of the invention concise.

After a method of forming a three-dimensional image according to acomparative example will be described first and the problems of themethod according to the comparative example are verified, thecharacteristics and effects of the method of forming a three-dimensionalimage according to this embodiment will be described.

FIGS. 2A, 2B, and 2C are schematic plan views illustrating a method offorming a three-dimensional image according to a comparative example,and FIGS. 3A, 3B, 3C, and 31) are schematic cross-sectional viewsillustrating the method of forming a three-dimensional image accordingto the comparative example.

For example, a three-dimensional image where an image of a dog andletters of “A”, “B”, and “C” printed on the surface of a thermallyexpandable sheet bulge to a uniform height as shown in FIG. 2 is formedin the method of forming a three-dimensional image according to thecomparative example of the invention. In this case, first, as shown inFIG. 2A, the image of the dog and the letters are formed (printed) witharbitrary colors on the surface of the thermally expandable sheet. Then,mirror images, which are inverted images of the image of the dog and theletters formed on the surface of the thermally expandable sheet, areformed as shown in FIG. 2B and these mirror images are formed (printed)with inks or toners containing black components, which are set to thesame density, on the back of the thermally expandable sheet. After that,the thermally expandable sheet is uniformly irradiated with light, whichhas a predetermined intensity, from the back of the thermally expandablesheet, so that thermal energy is generated according to the densities ofthe black component of the mirror images. As a result, the regions ofthe thermally expandable layer corresponding to the mirror images areheated and expanded as shown in FIG. 2C.

Here, when the bulge height of the thermally expandable layer, whichexpands due to the selective heating of the thermally expandable layercaused by the light irradiation of the thermally expandable sheet,depends on only the densities of the black component of the mirrorimages formed on the back of the thermally expandable sheet, it isexpected that the bulge height become uniform if the black components ofthe mirror images are set to the same density as shown in FIG. 2B.However, even though the black components of the mirror images are setto the same density, there is a case where the bulge heights of “A”,“B”, and “C” are not uniform and exceed an originally scheduled bulgeheight H as shown in FIG. 2C.

According to the verification of a variation in the bulge height that isperformed by the inventor, the bulge height of the surface of thethermally expandable sheet depends on not only the density of the blackcomponent of the mirror image formed on the back of the thermallyexpandable sheet but also the density of the black component containedin the colored image formed on the surface of the thermally expandablesheet. For this reason, it is found out that a variation occurs in thebulge height.

In more detail, as shown in FIG. 3A, arbitrary colored images 33 areformed on the surface, which corresponds to a thermally expandable layer32, of a thermally expandable sheet 30 where the thermally expandablelayer 32 is coated and formed on one surface of a base sheet 31 (theupper surface in FIG. 3A) as in the case shown in FIG. 2A. Here, thecolored image 33 is not limited to a case where a colored image isformed with a single color and set to the same density (see a coloredimage 33 shown on the left side in FIG. 3A), and may be a colored imagewhere regions 33 a to 33 c having arbitrary densities according topatterns or the like are set on the basis of surface image data (see acolored image 33 shown on the right side in FIG. 3A).

Meanwhile, as shown in FIG. 3B, mirror images 34 of the colored images33 are formed on the back of the thermally expandable sheet 30, whichcorresponds to the base sheet 31, so as to correspond to the coloredimages 33 formed on the surface of the thermally expandable sheet 30.Here, the densities of the mirror images 34 are set on the basis of onlya bulge height scheduled on the surface of the thermally expandablesheet 30. That is, as in the case shown in FIG. 2B, the mirror images 34are formed so as to have the same density regardless of the densities ofthe colored images 33.

Further, as shown in FIG. 3C, the thermally expandable sheet 30 isuniformly irradiated with light LT, which includes infrared wavelengthsand has a predetermined intensity, from the back on which the mirrorimages 34 are formed, so that thermal energy is generated in the mirrorimages 34. As a result, the regions of the thermally expandable layer 32corresponding to the mirror images 34 are expanded (foamed). At thistime, not only the thermal energy, which is generated in the mirrorimages 34 formed on the back of the thermally expandable sheet 30, butalso the thermal energy, which is generated in the colored images 33formed on the surface of the thermally expandable sheet 30 due to theirradiation of the light LT, is transferred to the regions of thethermally expandable layer 32 on which the colored images 33 are formed.Here, since the amount of the thermal energy, which is generated andtransferred from the colored images 33, varies according to thedensities of the black component (that is, a material having a highphotothermal conversion property such as carbon black) contained in therespective regions 33 a to 33 c corresponding to the patterns or thelike, a difference occurs in the expansion of the microcapsules of thethermally expandable layer 32 as shown in FIG. 3D and a variation occursin the bulge height of the thermally expandable layer 32 as in the caseshown in FIG. 2C. For this reason, there is a problem in that anintended bulge height H is not obtained.

Furthermore, the inventor has analyzed the tendency of the influence ofthe densities of the colored images, which are formed on the surface ofthe thermally expandable sheet, on the bulge height of the thermallyexpandable layer in detail by further performing verification.

FIGS. 4A and 4B are views illustrating an analytical method of themethod of forming a three-dimensional image according to the comparativeexample, and FIG. 5 is a view illustrating the concept of a dataprocessing method of a method of forming a three-dimensional imageaccording to this embodiment (the results of the analysis of thecomparative example).

That is, as shown in FIG. 4A, test charts, of which the densities of theblack component are set to 0%, 20%, 40%, 60%, 80%, and 100% so as tovary, are formed on the surface of the thermally expandable sheet (seethe left side in FIG. 4A), and a test chart set to a specific density(any one of 0%, 20%, 40%, 60%, 80%, and 100%) is formed on the back ofthe thermally expandable sheet so as to correspond to each of the testcharts (see the right side in FIG. 4A). Here, as surrounded in FIG. 4Aby a dotted line, each of the combinations of the test charts that areformed on the surface of the thermally expandable sheet and havedifferent densities, and the test charts that are formed on the back ofthe thermally expandable sheet and have specific densities is referredto as a group. In FIG. 4A, a case where the density on the back is 100%is defined as a group G1, a case where the density on the back is 80% isdefined as a group G2, a case where the density on the back is 60% isdefined as a group G3, a case where the density on the back is 40% isdefined as a group G4, and a case where the density on the back is 20%is defined as a group G5. A bulge height, when each of the groups isirradiated with light, is analyzed. Meanwhile, ink containing carbonblack, which has a high photothermal conversion property, is used toform the test charts that are formed on the surface and the back of thethermally expandable sheet.

It has been found that the bulge height of the thermally expandablelayer is affected by the density on the surface and tends to increasesubstantially in proportion to the density on the surface in any groupas shown in FIG. 4B when the thermally expandable sheet where the testcharts having the predetermined densities are formed on the surface andthe back is heated by the irradiation of light performed from the backas described above.

Here, in the groups G1 to G3 that have a relatively high density on theback of 60 to 100%, the bulge height of the thermally expandable layeris greatly affected by the density on the back rather than the densityon the surface. Further, in the groups G4 and G5 that have a relativelylow density on the back of 20 to 40%, the bulge height of the thermallyexpandable layer is greatly affected by the density on the surfacerather than the density on the back. Furthermore, when the density ofthe back is lower than the density on the surface, generally, the bulgeheight of the thermally expandable layer is greatly affected by thedensity on the surface in any group. The results of analysis shown inFIG. 5 are obtained about the degree of the influence (a ratio of therelative influence) of the density on the surface on the bulge height ofthe thermally expandable layer.

In the method of forming a three-dimensional image according to theinvention, the density of the black component of the mirror image formedon the back is adjusted on the basis of the content of verification andthe results of analysis shown in FIGS. 4 and 5 in anticipation of (inconsideration of) the influence of the density on the surface so thatthe originally scheduled bulge height can be achieved even when thebulge height of the thermally expandable layer is affected by thedensity of the black component contained in the colored image formed onthe surface of the thermally expandable sheet.

Specifically, when the bulge height of the thermally expandable layer isincreased by, for example, 20% as compared to the scheduled bulge heightdue to the influence of the density of the black component contained ina specific region of the colored image, the density of the blackcomponent of a specific portion of the mirror image corresponding to theregion is set so that the bulge height is reduced by 20%.

FIGS. 6A, 6B, and 6C are schematic plan views showing a specific exampleof the method of forming a three-dimensional image according to thisembodiment, and FIGS. 7A, 7B, 7C, and 7D are schematic cross-sectionalviews showing a specific example of the method of forming athree-dimensional image according to this embodiment. Here, the sameelements as those of the above-mentioned comparative example (see FIGS.2 and 3) are denoted by the same reference numerals when beingdescribed.

A data processing method, which adjusts and sets the density of a blackcomponent of a mirror image formed on the back of a thermally expandablesheet on the basis of the same content of verification and the sameresults of analysis as described above, is performed in the method offorming a three-dimensional image according to the invention. That is,when a three-dimensional image where an image of a dog and letters of“A”, “B”, and “C” printed on the surface of a thermally expandable sheetbulge to a uniform height is formed as in the above-mentionedcomparative example, the image of a dog and the letters are formed(printed) first with arbitrary colors on the surface of the thermallyexpandable sheet on the basis of surface image data as shown in FIG. 6A.

Then, as shown in FIG. 6B, mirror images, which are a print image of thedog of the surface and inverted print images of the letters, are formedon the back of the thermally expandable sheet on the basis of thesurface image data. Further, the density data of the black components,which are contained in the print image of the dog of the surface and theletters, are extracted and the bulge height (foam height) data of thethermally expandable layer, which are scheduled in the print image ofthe dog and the letters, are extracted. Furthermore, the densities ofthe black components of the mirror images formed on the back are set onthe basis of the density data, the bulge height data, theabove-mentioned content of verification, and the above-mentioned resultsof analysis on that a scheduled bulge height is achieved in anticipationof (in consideration of) the influence of the densities of the printimage of the dog of the surface and the letters on the bulge height ofthe thermally expandable layer.

That is, when the bulge height of the thermally expandable layer isaffected by the density on the surface, a ratio of the change of thebulge height from the scheduled bulge height is calculated and thedensity of the black component of the back is adjusted according to theratio. Specifically, for example, when the bulge height of the thermallyexpandable layer is increased due to the density on the surface, a rateof increase in the bulge height is calculated and the density on theback is set to a low level according to the rate of increase in thebulge height so that the rate of increase in the bulge height issubstantially cancelled (offset). Alternatively, adjustment forincreasing or reducing the density on the back is performed inconsideration of the rate of increase in the bulge height. Mirror imagesare formed (printed) on the back of the thermally expandable sheet onthe basis of the back image data where density is set in this way.

After that, the thermally expandable sheet is uniformly irradiated withlight, which has a predetermined intensity, from the back of thethermally expandable sheet, so that the corresponding regions of thethermally expandable layer are heated and expanded as shown in FIG. 6Cby the thermal energy generated according to the densities of the mirrorimages formed on the back and the thermal energy generated according tothe densities of the print image of the dog of the surface and theletters. At this time, since the density on the back is set on the basisof the density on the surface by the above-mentioned data processingmethod, the total amount of heat that is transferred to the thermallyexpandable layer from the surface and the back of the thermallyexpandable sheet is set to the amount of heat that allows the thermallyexpandable layer to expand to a scheduled bulge height.

Accordingly, it is possible to form a good three-dimensional image wherethe thermally expandable layer expands to a uniform and scheduledintended bulge height H in any of the patterns of the print image of thedog and the letters as shown in FIG. 6C.

Further, in the method of forming a three-dimensional image according tothe invention, as shown in FIGS. 7A, 7B, 7C, and 7D, colored images 33formed on the surface of the thermally expandable sheet 30 are notlimited to a case where the colored images are formed with a singlecolor, and it is possible to expand the thermally expandable layer to auniform and intended bulge height H even when regions having arbitrarydifferent densities are set according to patterns or the like.

That is, as shown in 7A, arbitrary colored images 33 are formed on thesurface of the thermally expandable sheet 30 as in the case shown inFIG. 6A. Here, in the colored image 33, regions 33 a to 33 c havingarbitrary different densities according to patterns or the like are seton the basis of the surface image data (see a colored image 33 shown onthe right side in FIG. 7A).

Furthermore, as shown in FIG. 7B, a mirror image 34, which includesspecific portions 34 a to 34 c of which the densities are set by theabove-mentioned data processing method, are formed on the back of thethermally expandable sheet 30 so as to correspond to the respectiveregions 33 a to 33 c that are set in the colored image 33 formed on thesurface. Here, The densities of the respective specific portions 34 a to34 c of the mirror image 34 are set on the basis of the densities of therespective regions 33 a to 33 c of the colored image 33 formed on thesurface, a bulge height scheduled on a portion of a thermally expandablelayer 32 corresponding to the respective regions 33 a to 33 c, theabove-mentioned content of verification, and the above-mentioned resultsof analysis so that an originally scheduled bulge height is achieved inanticipation of the influence of the densities of the respective regions33 a to 33 c of the colored image 33, which is formed on the surface, onthe bulge height of the thermally expandable layer.

That is, when the scheduled bulge height is denoted by H, the density ofthe specific portion 34 a is set in consideration of thermal energygenerated in the region 33 a of the colored image 33 formed on thesurface by the irradiation of light LT performed from the back of thethermally expandable sheet 30 as shown in FIG. 7C so that the totalamount of the thermal energy and the thermal energy generated in thespecific portion 34 a of the mirror image 34 formed on the back so as tocorrespond to the region 33 a becomes an amount capable of expanding aregion of the thermally expandable layer 32, which corresponds to theregion 33 a and the specific portion 34 a, to the scheduled bulge heightH. The densities of the specific portions 34 b and 34 c are also set inconsideration of the thermal energy generated in the respective regions33 h and 33 c of the colored image 33 formed on the surface so that aregion of the thermally expandable layer 32 corresponding to the portion34 b and the specific portion 34 c can expand to the scheduled bulgeheight H.

Further, as shown in FIG. 7C, the thermally expandable sheet 30 isuniformly irradiated with light LT, which has a predetermined intensity,from the back, so that thermal energy is generated in the colored image33 and the mirror image 34. As a result, the regions of the thermallyexpandable layer 32 corresponding to the colored image 33 and the mirrorimage 34 are expanded (foamed). At this time, since the densities of therespective specific portions 34 a to 34 c of the mirror image 34 are seton the basis of the densities set in the respective regions 33 a to 33 cof the colored image 33, substantially uniform thermal energy istransferred to the region of the thermally expandable layer 32corresponding to the colored image 33, so that the microcapsules areuniformly expanded as shown in FIG. 7C. Accordingly, it is possible toform a good three-dimensional image where the thermally expandable layerexpands to the uniform in and scheduled intended bulge height H.

Meanwhile, the method of forming a three-dimensional image, which canexpand the thermally expandable layer to the uniform and intended bulgeheight H even when regions having different densities are set accordingto patterns or the like of a colored image such as a color image, hasbeen described in this embodiment. However, the invention is not limitedthereto. That is, even when a three-dimensional image where regionshaving different densities are set according to patterns or the like ofa colored image such as a color image and the respective regions bulgeto different heights is formed, it is possible to form a goodthree-dimensional image where the respective regions of the coloredimage bulge to scheduled intended bulge heights, by adjusting thedensities of the respective specific portions of the mirror image on thebasis of the same technical idea as the technical idea of theabove-mentioned embodiment and the bulge heights and densities of therespective regions and generating thermal energy corresponding to thebulge heights from the colored image and the mirror image thereof.

<Apparatus for Forming Three-Dimensional Image>

Next, an apparatus for forming a three-dimensional image, which canrealize the above-mentioned method of forming a three-dimensional image,will be described.

FIGS. 8A and 8B are schematic views showing an example of a printer thatis applied to an apparatus for forming a three-dimensional imageaccording to the invention. FIG. 8A is a perspective view showing theschematic structure of the printer applied to this embodiment, and FIG.8B is a cross-sectional view showing the schematic structure of theprinter applied to this embodiment. FIG. 9 is a schematic view showingan example of a printing mechanism of the printer applied to thisembodiment. Here, FIG. 9 is a detailed perspective view of a portion IXshown in FIG. 8B (in this specification, “IX” is used as a referencenumeral corresponding to a roman numeral “9” shown in FIG. 8 forconvenience).

At least the image data generation processing (S101), the back imagedata generation processing (S102), and the back image formationprocessing (S103) of the above-mentioned method of forming athree-dimensional image can be performed by a printer 100 shown in FIG.8. The printer 100 applied to this embodiment is an inkjet printerhaving a function of, for example, a word processor. Specifically, theprinter 100 includes a printer body 110 and a keyboard 130 as shown inFIGS. 8A and 8B.

As shown in, for example, FIGS. 8A and 8B, the printer body 110 mainlyincludes a box-shaped housing, a display panel 111, a display panelreceiving portion 112, a sheet feed tray 113, a sheet discharge port114, a card slot 115, a printing mechanism (see FIG. 9) 120, and acontrol section (not shown; see FIG. 10).

The display panel 111 is formed of, for example, a liquid crystaldisplay panel, and is mounted so as to be rotated relative to theprinter body 110 about a hinge portion 111 a that is provided on oneside. Data input from the keyboard 130, a menu screen required forvarious settings, various images such as photographic images providedthrough a memory card, and data required for the printer are displayedon the display panel 111. The display panel receiving portion 112 isprovided at the upper surface portion (on the upper surface of FIG. 8)of the printer body 110. When the printer 100 is not used, the displaypanel 111 is rotated and received in the display panel receiving portion112.

The sheet feed tray 113 is provided on the rear portion (the right sidein FIG. 8B) of the printer body 110. The thermally expandable sheets 30,which have been described in the above-mentioned embodiment, arereceived one by one in the sheet feed tray 113 from an opening portion113 a formed at the upper portion of the sheet feed tray 113, orreceived in the sheet feed tray 113 from an opening portion 113 a whilea plurality of thermally expandable sheets 30 overlap each other. Apick-up roller 113 b is provided in the sheet feed tray 113. The pick-uproller 113 b feeds the thermally expandable sheets 30, which arereceived in the sheet feed tray 113 while overlapping each other, to theprinting mechanism 120, which is provided in the printer body 110, oneby one.

The sheet discharge port 114 is formed at the lower portion of the frontsurface (the left side in FIG. 8B) of the printer body 110. Thethermally expandable sheet 30, which is printed by the printingmechanism 120 provided in the printer body 110, is discharged to theoutside through the sheet discharge port 114. The card slot 115 isformed at the front surface of the printer body 110. When a memory card(not shown) is inserted into the card slot 115, image data or the likeare read or written.

Further, as shown in FIG. 8B, a sheet conveying path 116 along which thethermally expandable sheet 30 fed by the pick-up roller 113 b providedin the sheet feed tray 113 is conveyed and guided is provided in theprinter body 110. For example, an inkjet printing mechanism 120 isprovided on the sheet conveying path 116. A pair of sheet feed rollers121 and a pair of sheet discharge rollers 122, which convey thethermally expandable sheet 30, are disposed on the sheet feed side (theright side in FIG. 8B) and the sheet discharge side (the left side inFIG. 8B) of the printing mechanism 120, respectively.

As shown in FIG. 9, the printing mechanism 120 includes a carriage 123that reciprocates in the direction of an arrow A orthogonal to the sheetconveying path 116. A printing head 124, which performs printing, and anink cartridge 125 are mounted on the carriage 123. The ink cartridge 125is formed of individual cartridges that store color inks, such asyellow, magenta, cyan, and black inks, or is formed of a singlecartridge in which ink chambers for the respective colors are formed.The printing head 124, which includes nozzles for discharging therespective color inks, is connected to the respective cartridges or therespective ink chambers, Here, in this embodiment, a material having ahigh photothermal conversion property such as carbon black is applied asa black ink stored in the ink cartridge 125.

Further, the carriage 123 is supported by a guide rail 126 so as toreciprocate as described above. When a driving belt 127, which isprovided parallel to the extending direction of the guide rail 126, isdriven, the printing head 124 and the ink, cartridge 125 mounted on thecarriage 123 reciprocate in the same direction as the carriage 123, thatis, in the direction of the arrow A orthogonal to the sheet conveyingpath 116.

Print data or a control signal is sent to the printing head 124 from thecontrol section, which is provided in the printer body 110, through aflexible cable 128. Here, the thermally expandable sheet 30 isintermittently conveyed in the direction of an arrow B of FIG. 9 by thepair of sheet feed rollers 121 and the pair of sheet discharge rollers122 as described above. Furthermore, during the stop of the intermittentconveyance of the thermally expandable sheet 30, the printing head 124ejects ink droplets when being close to the thermally expandable sheet30 while the printing head 124 reciprocates so as to correspond to thedrive of the driving belt 127. In this way, the printing head 124 printsan image, which corresponds to the print data, on the surface or theback of the thermally expandable sheet 30. An intended image (a coloredimage or a mirror image) is formed (printed) on the entire surface ofthe thermally expandable sheet 30 by the repetition of the intermittentconveyance of the thermally expandable sheet 30 and the printing of theprinting head 124 during the reciprocation of the printing head 124. Thethermally expandable sheet 30 on which a predetermined image has beenprinted by the printing mechanism 120 is discharged to the outside ofthe printer body 110 from the sheet discharge port 114 that ispositioned on the sheet discharge side of the sheet conveying path 116as shown in FIGS. 8A and 8B.

Moreover, as shown in FIGS. 8A and 8B, the keyboard 130 is disposed onthe near side in front of the printer body 110 (on the left side inFIGS. 8A and 8B). The keyboard 130 is provided with data input keys 131,function keys 132, and the like that are necessary to perform variousfunctions, such as the input, the editing, the printing, or the like ofdocument data when the printer body 110 is used as a word processor.

Next, the control section provided in the printer body 110 of theabove-mentioned printer 100 will be described.

FIG. 10 is a functional block diagram of an example of the printerapplied to this embodiment.

As shown in FIG. 10, the above-mentioned printer 100 mainly includes acentral processing circuit (hereinafter, abbreviated to a “CPU”) 101, aread-only memory (hereinafter, abbreviated to a “ROM”) 102 that isconnected to the CPU 101, a random access memory (hereinafter,abbreviated to a “RAM”) 103, an image processing unit 104, a datainput/output unit 105, a printer controller 106, a read controller 107,the above-mentioned display panel 111, and the above-mentioned keyboard130. Here, the CPU 101, the ROM 102, the RAM 103, the image processingunit 104, the data input/output unit 105, the printer controller 106,and the read controller 107 correspond to the control section of theprinter 100 applied to this embodiment.

The ROM 102 stores a system program related with the control of theoperation of the printer 100. The CPU 101 controls the operation of eachunit of the printer 100 by sending command signals to other functionalblocks, which are connected to the CPU 101, according to this systemprogram. Further, the RAM 103 temporarily stores various data, numericalvalues, and the like that are generated by the CPU 101 and the likeduring the control of the operation of the printer.

The image processing unit 104 performs the image data generationprocessing (S101) of the above-mentioned method of forming athree-dimensional image. That is, image data (back image data) of amirror image that is to be an inverted image of a colored image aregenerated on the basis of the image data (surface image data) of acolored image that is to be a target of a three-dimensional image inputfrom the outside of the printer body 110 through the card slot 115 andthe like and displayed on the display panel 111 or stored in the RAM 103and the like. At this time, on the basis of the density data of a blackcomponent that are set in a specific region or pixels such as a patternor the like of the colored image and bulge height (foam height) datathat are scheduled in the specific region or the like when athree-dimensional image is formed, the density of a black component of aspecific portion of a mirror image corresponding to the specific regionor the like is set by the data processing method of the above-mentionedmethod of forming a three-dimensional image. In this way, the imageprocessing unit 104 has a function of adjusting the density of a coloredimage that is formed on a thermally expandable sheet or a mirror imageof the colored image.

The data input/output unit 105 inputs and outputs print commands, whichare related with the image data, between the printer and an externalcommunication device (not shown), such as a notebook personal computeror a desktop personal computer. The printer controller 106 is connectedto the printing mechanism 120, and controls the discharge of the ink ofthe printing head 124 on the basis of the data of an image that is to bea target to be printed. Further, the printer controller 106 controls theconveyance of the thermally expandable sheet 30 to the sheet dischargeside by controlling the reciprocation of the carriage 123 on which theprinting head 124 is mounted and the drive of the pair of sheet feedrollers 121 and the pair of sheet discharge rollers 122. The readcontroller 107 is connected to the card slot 115, reads image data froma memory card (not shown) inserted into the card slot 115, and sends theimage data to the CPU 101 or the image processing unit 104.

According to the printer 100 having the above-mentioned configuration,it is possible to form an image (a colored image or a mirror image),which has a predetermined density corresponding to the image data, onthe surface or the back of the thermally expandable sheet 30 that is fedfrom the sheet feed tray 113. Meanwhile, a case where the printer 100has a function of printing an image only on one surface of a sheet hasbeen described in this embodiment. That is, in the surface imageformation processing (S102) of the above-mentioned method of forming athree-dimensional image, the thermally expandable sheet 30 is fed sothat the surface of the thermally expandable sheet 30 faces the printinghead 124. Accordingly, an intended colored image is printed on thesurface of the thermally expandable sheet 30. Moreover, in the backimage formation processing (S103), the thermally expandable sheet 30 isturned upside down and is fed so that the back of the thermallyexpandable sheet 30 faces the printing head 124. Accordingly, a mirrorimage corresponding to the colored image formed on the surface of thethermally expandable sheet 30 is printed on the back thereof.

The printer applied to the apparatus for forming a three-dimensionalimage according to the invention is not limited thereto, and may beprovided with sheet reversing mechanisms for double-sided printing onthe sheet feed side and the sheet discharge side of the printingmechanism 120 of the printer body 110 as shown in FIGS. 8B and 9. Thatis, in the printing mechanism 120, the thermally expandable sheet 30 onwhich printing has been completed on the surface (or the back) and whichis conveyed to the sheet discharge side may be conveyed in the directionopposite to the arrow B and then return to the sheet feed side. Thethermally expandable sheet 30 may be reversed and turned upside down onthe sheet feed side, printing may be performed on the back (or thesurface) of the thermally expandable sheet 30, and the thermallyexpandable sheet 30 may be discharged from the sheet discharge port 114.According to this, it is possible to omit a work for turning thethermally expandable sheet 30, which is discharged after being subjectedto printing on one surface thereof, upside down and receiving thethermally expandable sheet 30 in the sheet feed tray 113 again.

Further, a case where the image data generation processing (S101) of themethod of forming a three-dimensional image according to this embodimentis performed by the image processing unit 104 provided in the controlsection of the printer 100 has been described in the above-mentionedembodiment. However, the invention is not limited thereto. That is, theabove-mentioned image data generation processing may be performed in anexternal communication device such as a personal computer connected tothe printer 100 through the data input/output unit 105, the image data(back image data) of a mirror image or the density data thereof may besent to the printer 100, and the mirror image of the colored image maybe formed (printed) on the back of the thermally expandable sheet 30 soas to have a predetermined density.

Furthermore, a case where the image data generation processing (S101),the surface image formation processing (S102), and the back imageformation processing (S103) of the method of forming a three-dimensionalimage according to this embodiment are performed by the printer 100 hasbeen described in the above-mentioned embodiment. However, the inventionis not limited thereto. That is, for example, as shown by a two-dotchain line in FIG. 8B, a light source unit 140 such as a halogen lampmay be disposed on the upper surface side or the lower surface side ofthe sheet conveying path 116 (or the thermally expandable sheet 30) onthe sheet discharge side of the printing mechanism 120. Here, forexample, as shown by a two-dot chain line in FIG. 10, the light sourceunit 140 emits light, which has a predetermined intensity, on the basisof a command from the CPU 101 according to the conveyance of thethermally expandable sheet 30.

In this configuration, the thermally expandable sheet 30 where apredetermined colored image and a predetermined mirror image have beenformed on the surface and the back through the image data generationprocessing (S101), the surface image formation processing (S102), andthe back image formation processing (S103) is irradiated with uniformlight from the back thereof, thereby performing the lightirradiation/heating processing (S104) for forming a three-dimensionalimage by expanding the thermally expandable layer 32 of the thermallyexpandable sheet 30 so that the thermally expandable layer 32 bulges toa predetermined bulge height. That is, in a single printer 100, it ispossible to collectively perform all the processes of theabove-mentioned method of forming a three-dimensional image.

Having described and illustrated the principles of this application byreference to one preferred embodiment, it should be apparent that thepreferred embodiment may be modified in arrangement and detail withoutdeparting from the principles disclosed herein and that it is intendedthat the application be construed as including all such modificationsand variations insofar as they come within the spirit and scope of thesubject matter disclosed herein.

The invention claimed is:
 1. A method of forming a three-dimensionalimage, the method comprising: forming a first print image on a firstsurface of a thermally expandable sheet which includes a thermallyexpandable layer formed on one surface of a base sheet; forming a secondprint image on a region of a second surface of the thermally expandablesheet, wherein the second print image is a mirror image of the firstprint image, wherein the region of the second surface corresponds to thefirst print image of the first surface, and wherein a density of a lightabsorbing photothermal conversion material contained in the second printimage is set based on a density of a color image photothermal conversionmaterial contained in the first print image; and forming athree-dimensional image of the first print image by selectivelyexpanding the thermally expandable layer with a thermal energy that isgenerated in both the first print image and the second print image whenirradiating the thermally expandable sheet with light from the secondsurface of the thermally expandable sheet, wherein the thermal energygenerated in the first print image and the second print image isdependent upon the density of the color image photothermal conversionmaterial contained in the first print image and the density of the lightabsorbing photothermal conversion material contained in the second printimage, respectively, wherein the second print image is formed with afirst density of the light absorbing photothermal conversion material ata first part of the second print image and with a second density of thelight absorbing photothermal conversion material at a second part of thesecond print image, wherein the first density of the light absorbingphotothermal conversion material of the second print image is lower thanthe second density of the light absorbing photothermal conversionmaterial of the second print image, wherein the first part of the secondprint image corresponds to a first part of the first print image, andthe second part of the second print image corresponds to a second partof the first print image, wherein a first density of the color imagephotothermal conversion material of the first part of the first printimage is higher than a second density of the color image photothermalconversion material of the second part of the first print image, andwherein the three-dimensional image of the first print image is formedby uniformly irradiating the thermally expandable sheet with the lightso that the thermally expandable sheet corresponding to the first partof the first print image expands to a same bulge height as the thermallyexpandable sheet corresponding to the second part of the first printimage.
 2. The method according to claim 1, wherein the three-dimensionalimage of the first print image is formed by selectively expanding thethermally expandable layer with the thermal energy that is generated bythe light that is radiated to the thermally expandable sheet accordingto the density of the color image photothermal conversion materialcontained in the first print image and the density of the lightabsorbing photothermal conversion material contained in the second printimage.
 3. The method according to claim 2, wherein the density of thelight absorbing photothermal conversion material contained in the secondprint image is set in consideration of the thermal energy, which isgenerated according to the density of the color image photothermalconversion material contained in the first print image, so that thethermally expandable layer expands to achieve a preset predeterminedbulge height.
 4. The method according to claim 3, wherein the firstprint image is a colored image and includes regions that have differentdensities of the color image photothermal conversion material, andwherein the second print image includes specific portions wheredensities of the light absorbing photothermal conversion material areset so as to correspond to the regions having the different densities ofthe first print image.
 5. The method according to claim 4, wherein thelight includes infrared wavelengths.
 6. The method according to claim 2,wherein the density of the light absorbing photothermal conversionmaterial contained in the second print image is set to be inverselyproportional to the density of the color image photothermal conversionmaterial contained in the first print image, so that the thermallyexpandable layer expands to achieve a preset predetermined bulge height.7. The method according to claim 3, wherein the light includes infraredwavelengths.
 8. The method according to claim 1, wherein the density ofthe light absorbing photothermal conversion material contained in thesecond print image is set in consideration of the thermal energy, whichis generated according to the density of the color image photothermalconversion material contained in the first print image, so that thethermally expandable layer expands to achieve a preset predeterminedbulge height.
 9. The method according to claim 8, wherein the firstprint image is a colored image and includes regions that have differentdensities of the color image photothermal conversion material, andwherein the second print image includes specific portions wheredensities of the light absorbing photothermal conversion material areset so as to correspond to the regions having the different densities ofthe first print image.
 10. The method according to claim 8, wherein thelight includes infrared wavelengths.
 11. The method according to claim1, wherein the first print image is a colored image and includes regionsthat have different densities of the color image photothermal conversionmaterial, and wherein the second print image includes specific portionswhere densities of the light absorbing photothermal conversion materialare set so as to correspond to the regions having the differentdensities of the first print image.
 12. The method according to claim11, wherein the light includes infrared wavelengths.
 13. The methodaccording to claim 1, wherein the density of the light absorbingphotothermal conversion material contained in the second print image isset to be inversely proportional to the density of the color imagephotothermal conversion material contained in the first print image, sothat the thermally expandable layer expands to achieve a presetpredetermined bulge height.